Apparatus for cleaning heat exchange means



A. H. KIRKBY Aug. 16, 1960 APPARATUS FOR CLEANING HEAT EXCHANGE MEANSFiled NOV. 18, 1955 3 Sheets-Sheet l INVENToR. Alberr H. Kirkby ATTORNEYug. 16, 1960 A. H. KIRKBY APPARATUS FOR CLEANING HEAT EXCHANGE MEANSFiled Nov. 18, 1955 3 Sheets-Sheet 2 FIG.7

INVENToR.

AI ber'r H. Kirkby ATTORNEY Aug. 16, 1960 A. H. KIRKBY 2,949,282

APPARATUS EOE CLEANING HEAT EXCHANGE MEANS Filed Nov. 18, 1955 3Sheets-Sheet 3 FIG. 8

INVENTOR.

Alber'r H.Kirkby l ATTORNEY APPARATUS FR CLEANNS HEAT EXCHANGE MEANSAlbert H. Kirkby, Mill Hiii, London, England, assignor to The Babcock d:Wilcox Company, New York, NSY., a corporation of New iersey Filed Nov.18, 1955, Sera No. '547,796

Claims priority, application Great Britain Nov. 23, 1954 3 Claims. (Cl.257-1) This invention relates to an improved apparatus for cleaning heatexchange means and is concerned with apparatus for cleaning heatexchange means disposed in an upright gas pass, the apparatus comprisingmeans for supplying to the pass solid cleaning particles in order thatthe particles may fall Within the pass and in falling may impact withdeposits on surfaces of the heat exchange means to be cleaned.

Hitherto the cleaning particles have been fed into the pass through theroof thereof, so that the rain of particles falls through the wholepass. In practice, however, conditions may arise such that heat exchangesurfaces near the bottom of a pass suier more acutely from deposits thanheat-exchange surfaces near the top of the pass and it may be desirableto act with the cleaning particles more strongly on a lowermost tubebank or lowermost tube banks than on an adjacent tube bank or adjacenttube banks disposed higher up in the pass. Then again,it may be deemeddesirable to avoid showering cleaning particles onto a tube bank or tubebanks nearest the top of the pass, either because the action of theparticles on lthe said bank or banks is unnecessary or because theaction is liable to lead to ill elects.

The present invention includes apparatus for cleaning heat exchangemeans disposed in an upright gas pass, comprising means for supplying tothe pass solid cleaning particles in order that the particles may fallwithin the pass and in falling may impact with deposits on surfaces ofthe heat exchange means to be cleaned, wherein provision is made forintroducing cleaning particles into the pass at a region betweenvertically spaced tube banks contained in the pass.

The invention also includes apparatus for cleaning heat exchange meansdisposed in an upright gas pass, comprising means for supplying tothepass solid cleaning particles in order .that the particles may fallwithin the pass and in falling may impact with deposits on surfaces ofthe heat exchange means to be cleaned, wherein provision is made forintroducing cleaning particles at a plurality of regions aboverespective tube banks vertically spaced from one another in the gaspass.

The invention further includes apparatus for cleaning heat exchangemeans disposed in an upright gas pass, comprising means for supplying to.the pass solid cleaning particles in order that the particles may fallwithin the pass and in falling may impact with deposits on surfaces ofthe heat exchange means to be cleaned, wherein the solid cleaningparticle supply means include a tube arranged to receive particles borneby elastic fluid, to extend through a side wall of the pass and todirect the particles against a target member provided with means forimparting to the target member an oscillatory motion adapted to increasethe area over Which the cleaning particles are scattered.

The invention will now be described, by way of example, With referenceto the accompanying partly diagrammatic drawings, in which:

Figure 1 is a side elevation, partly in section of an upright gas passprovided with the cleaning apparatus of the present invention;

Figure 2 is a view of part of the apparatus shown in Figure 1 looking inthe direction of the arrows 2 showing the arrangement of entrainingnozzles and their associated cleaning particle cut oit valves;

Figure 3 is a side elevation of a part of a discharge tube and theassociated target member shown in Figure 1, to a larger scale than thatfigure;

Figure '4 is Yan end elevation of the discharge tube and target membershown in Figure 3;

Figure 5 is a view similar to that of Figure 3 but showing a detlectormember in addition to the target member;

Figure 6 is a side elevation showing part of a discharge tube and analternative arrangement of target member to that shown in Figure 3;

Figure 7 is an end elevation of the discharge tube' and target membershown in Figure 6; and

Figure 8 is a representation of an oscillating discharge tube suitablefor use in the apparatus shown in Figure 1. For the sake of clarity thedischarge tube is shown broken, the portions of the tube and therespective associated parts being displaced from one another in thedirec- `tion of the `axis of the tube.

ln Figure 1 of the drawings, an upright gas pass 1 is provided with heatexchange means comprising ventically spaced tube banks 4, 4A, 4B and 4Cof horizontal tube lengths arranged with adjacent rows in staggeredformation.- In a wall 6 of the gas pass is provided an upper gas inlet 2adjacent the roof of the pass and the lower end of the pass is providedwith a hopper bottom 5 adjacent the top of which is a gas outlet 3 fromthe pass.

The lower end of the hopper bottom is provided with cleaning particlecollecting means which may be of the nature disclosed in my co-pendingapplication, Serial No. 437,455, tiled lune 17, 1954, Thus `a particlecollec-ting duct 1t) is provided with means for the removal of particlesbelow a predetermined size and pieces of slag from the system, and isconnected by a chute 19 for the passage of cleaning particles of normalsize to a collecting bin 20 having an overiiow spout 22 and a hopperbottom li.

The lower end of the hopper 1i as is shown more clearly in Figure 2, isprovided with outlets respectively connected to entraining nozzles 13,13A, 13B and iSC, suitably of the nature disclosed in my said co-pendingapplication and arranged side by side, through the associated cut oilvalves 112, 112A, 12B and 12C. The entraining nozzles are respectivelyconnected at their supply ends to a source (not shown) of gaseousentraining iiuid under pressure through the iluid supply ducts i5, iSA,15B and 15C, and at their outlet ends to the cleaning particle conveyingducts iti, iA, MB and MC. The fluid supply ducts are each provided witha fluid supply control valve, suitably a butterfly valve, as is shown ati4 for the duct i5. The conveying ducts are respectively connected todownwardly inclined, cleaning particle discharge tubes 8, 5A, 8B and 8Cby means of associated lengths of suitably armoured flexible hose 17,17A, 117B and iIC.

The discharge tubes which are respectively provided at their dischargeends with target members 9, 9A, 9B and 9C described below in connectionwith Figures 2 and 3, pass through the associated openings 7, 7A, 7B and7C formed in the wall 6 respectively adjacent the regions above the tubebanks Il, 4A, 4B and 4C. The tubes are supported on the respectivecasing members 18, 18A, 18B and 118C which are rigidly attached to thewall 6.

Referring to Figures 3 and 4', the target member 9 comprises areplaceable "target plate 2S of wear resistant material spaced in thedirection of discharge from the discharge end of the downwardly inclinedtube 8 and inclined with respect to the longitudinal axis thereofupwardly and away from the vdischarge end. The target plate is locatedlon a back Aplate *'26, formed on support arm 25, by a spigot 29projecting from the back `plate an'd co-operating with a recess formedin the Yback ofthe target plate, and is rigidly attached to the backplate by studs (not shown). rthe support arm is removably attached tothe tube 8 close to its discharge end'by a split sleeve 27, clamped inlposition by Vbolts (not shown).

Elastic entrai'ning lliuid, 'suitably air or gas under -pressure, issupplied through the ducts l5, 15A, V345B and 15C to -the respectivenozzles where the cleaning particles are cntrained and carried throughthe associated ducts lo, ESA, '16B and 6C to the respective dischargetubes 8, SA, 8B and 3C. The butterfly valves in the ducts 15, 15A, 15Band 15C allow separate regulation of the supply of entrainin'g lfluid tothe associated nozzles and thereby allow separate regulation of thevelocity ot discharge of the fluid borne streams of cleaning particlesfrom their associated discharge tubes. 'l/'hen a cut 'ofi valve isclosed, the supply of entraining lluid to the associated nozzle isstopped by closing'the butterfly valve in the corresponding supply duct.

Since the cut olic andbutterlly valves associated with each dischargetube are separately operable from the cut oft and Vbutterfly valvesassociated with the other discharge tubes, cleaning particles may beselectively introduced to the respective regions above the tube banks.Moreover, the duration of the discharge from any one of the dischargetubes may separately be controlled by operation of the associated ycutoft' valve.

In the apparatus described, the necessity of providing means forseparating the 'cleaning ,particles from the Agaseous carrier fluidbefore discharging the cleaning particles above -a Vtube bank isavoided.

Referring to Figures l to 4 of the drawings, in operation the ftluidborne cleaning particles are discharged from the respective downwardlyinclined discharge tubes 8, 8A, 8B and 8C and impinge on the targetplates of the associated target members 9, 9A, 9B and 9C so that theparticles undergo changes in direction and are dispersed upwardly andsidewardly and lfollow shallow Ytrajectories through the regions abovethe vertically spaced tube banks 4, 4A, 4B and 4C, as schematicallyindicated by the broken `lines Z1, 21A, 23B and 21C, and fall over wideareas.

The conveying fluid may eect discharge of the 'cleaning particles fromthe tube at a high velocity of the order, say, of 100 feet per second.As a result, it is possible to throw particles deilected by the targetplate a considerable distance and an area of substantial length may beserved by a single tube and target plate. The cleaning particles fallthrough the tube banks, impacting with the deposits to be removed, andpass through the collecting duct 1l) at the lower end of the hopper 5and accumulate in the collection bin Ztl. Accumulations of slag andundersize cleaning particles may be removed from the collecting duct 1l)at intervals and additional particles added lto the system as isdescribed in my copending application, Serial No. 437,455.

The cleaning particles -are separately supplied vfrom the collectingmeans to the nozzles 13, lSA, l3B and 13C through the respective cut oitvalves 12, 12A, 32B and ZC.

In the embodiment shown in Figure of the drawings, the downwardlyVinclined tube 8 is provided, in addition to the target member, with adetlector member comprising a dellector :plate 30 located on a backplate 31 by a spigot 43. The plate 30 is rigidly supported on the backplate by studs (not shown) and located with respect to the tube 8 by asupport 4arm 32 which vextends from one part of the split sleeve `27`The dellector plate 30 is so positioned in the cleaning particle pathfrom the target plate 2S as to interfere with the stream of cleaningparticles after their impact with the target plate. In operation some ofthe particles leaving the target plate 28, impinge ou the dellectorplate 30 and are deflected downwardly so that they follow pathsditferent from those of particles trajected from the target plate alone.Wider dispersal of the cleaning particle stream may be attained, andheat exchange surfaces closer to the discharge tube 8 may be reached.

In the embodiment shown in Figures 6 and V7, the discharge tube 3 isupwardly inclined and the target member is disposed above the tube andformed with an impact surface inclined with respect to the axis of thetube and spaced in the direction of discharge from the discharge end ofthe tube. The target member comprises a replaceable target plate 41having a curved impact face and formed of wear resistant materiallocated on a back plate '40 by spigot 42 and rigidly attached lt'o'theback plate by studs (not shown). The back plate is provided with an arm37 which is mounted between the bifurcations 35, formed at t-he end of asupport arm 34, on a lbolt 3S. The bolt extends through slots 36 formedin the bifurcations and is provided with locking means 3'9 whereby thetarget plate may be clamped in vadjusted position with respect to thesupport arm 34 which is removably :attached to the discharge tube `closetoits discharge end by the split sleeve 33. The location of vthe targetplate with lrespect to the discharge end of tube 8 may be adjusted byloosing the locking means 39 and rotating the plate about the bolt 38or/and by sliding the bolt in the slots 36 before again clamping the arm37 in position. Furthermore, the target member 'may be rotated about thelongitudinal axis of the tube 8 by movement of the support arm 34 beforeclamping the vsplit sleeve 33. vrIfhe adjustments enable wear 'of theplate t'o 4be compensated land the dispersion Vcharacteristics of theplate with respect to the discharge stream to be varied.

In operation, the stream of fluid borne particles is directed` by theupwardly inclined discharge tube against the target plate, tand isdispersed downwardly and sidewardly onto the surfaces to be cleaned,ensuring cleaning of heating surfaces subjacent the discharge end of thetube 8. The tube and its target member may be adapted to spread thecleaning particles over a wide area and do not screen any part of thetube bank.

It will be understood that the number Vof discharge tubes above any onetube bank will depend on the area of surface to be cleaned, and that aplurality of spaced tubes may be positioned above the bank to ensurethat cleaning particles reach all port-ions of the tube bank. Forexample, when more than one tube is to be'pr'ovided at a region, thetube may be disposed in spaced relationship along one side of the gaspass, or `at least one tube may be provided at each of two oppositewalls of -t-he gas pass.

The dispersion characteristics of the target fand deflector plates maybe varied by using impact surfaces of different contours. The surfacesmay be hat, curved, or iluted, for example.

The quantity of cleaning particles discharged lover any one tube bankmust tfall through any Ibank lower in the pass. The lower banks aretherefore subject to the :greatest cleaning elect, and the upper bankswhich may carry little or no deposit are not subjected to unnecessarydischarges. In fact the scattering of cleaning particles onto heatexchange surfaces, for example, superheating surfaces in an upperportion of a pass constituting a high temperature zone may be avoided`and heat exchange surfaces at the bottom of a pass may be cleanedwithout eroding clean heat exchange surfaces Vhigher -up 'in lthe pass.

When the gas pass 'is of large area of cross-section, it

Anf.

and deector plates to reach all parts of the surfaces to be cleanedwhilst retaining a substantially uniform cleaning eiect over the wholesurface. An increase in the area eiectively cleaned by the dischargefrom one discharge tube 8 may be `attained by varying the position ofthe associated target member. An oscillating mechanism to attain thisend is shown in Figure 8 of the drawings in which the discharge tube 8,connected at its discharge end to the target member 9 and at its outerend to liexible hose connection 17, is rotatably mounted in -a carriermember 44 which itself is pivotally supported on trunnions 45 on a basemember (not shown) secured to a casing member such as 1S in Figure 1,and rotatable about horizontal axis 47 normal to the longitudinal axis66 of tube 8. The upper end of an operating link 63 is connected by balljoint 64 to an end of the carrier member 44 on la side of the axis 47remote from the target member 9. The lower end of operating link 63 isconnected by ball joint 62 to an arm 60 of a bell crank lever pivoted onpins 61 about a horizontal axis normal to axis 47. The other arm 59 ofthe bell crank lever is rotatably connected by pin joint 58 toconnecting link 57 which is rotatably connected to crank lever S5 by pinjoint 56. The crank lever 55 is rotatably mounted about a horizontalaxis `65 normal to axis 47.

Rigidly attached to the tube 8 close to the operating link 63 is a boss49 having a radius arm 48 connected at its outer end by ball joint 50 toone end of the connecting link 51 which is connected as its other end byball joint 52 to crank 53. The crank 53v is rotatably mounted abouthorizontal axis 54 which extends normally to axis 47.

In operation, rotation of the crank 55 about axis 65 causes angularoscillation of the tube 8 about axis 47 las indicated by the arrow 46.Rotation of the crank 53 about axis 54 causes angular oscillation of thetube 8 about its longitudinal axis 66 as is shown by arrow 67.

The path through which the beaten yzone formed by the cleaning particlesfalling from the discharge tube 8 moves, may be controlled by adjustingthe elfective lengths of cranks 53 and 55 and of the arms 59 and 60 ofthe bell crank lever. In this way the amplitudes of the oscillations maybe adjusted and consequently the area of heating surface over which thebeaten zone moves may be varied.

The rate rat which the beaten zone moves over the area determined by theamplitudes of the oscillations of the tube may be controlled by varyingthe speeds of rotation of the cranks 53 and 55 with respect to eachother and to this end the cranks are mounted on separate driving shafts.

While in accordance with the provision of the statutes I haveillustrated `and described herein the best form of the invention nowknown to me, those skilled in the art will understand that changes maybe made in the tformof the apparatus disclosed without departing fromthe spirit of the invention covered by my claims, and that certainfeatures of my invention m-ay sometimes be used to advantage without acorresponding use of other features.

What is claimed is:

1. Apparatus for cleaning heat exchange means including verticallyspaced banks of horizontally arranged tubes disposed in an upright gaspass wherein said vertically spaced banks of tubes are sulciently spacedfor transf verse distribution of solid cleaning particles completelyacross said gas pass, comprising means for supplying to the pass saidsolid cleaning particles in order that the particles may fall within thepass and in falling may impact with deposits on surfaces of the heatexchange means to be cleaned including separate particle discharge meanspositioned in each of said interbank spaces, and means for introducingcontrolled amounts of cleaning particles to each of said separateparticle discharge means.

2. Apparatus for cleaning heat exchange means including verticallyspaced banks of horizontally spaced tubes disposed in an upright gaspass wherein said vertically spaced banks of tubes are suiciently spacedfor transverse distribution of solid cleaning particles completelyacross said gas pass, comprising means for supplying to the pass saidsolid cleaning particles in order that the particles may fall Within thepass and in falling may impact with deposits on surfaces of the heatexchange means to be cleaned including separate particle discharge tubespositioned in each of said interbank spaces, the said solid cleaningparticle supply means including'a plurality of tubes arranged to receiveparticles borne by elastic uid, and means for regulating the amount ofcleaning particles delivered to each of said discharge tubes.

3. Apparatus according to claim 2 including a target member positionedadjacent the discharge end and in the path of flow from each of saidtubes, and means for oscillating each said target member about thelongitudinal axis of its individual tube and about a horizontal axistransverse to the longitudinal axis thereof.

References Cited in the tile of this patent UNITED STATES PATENTS1,373,750 McNeill Apr. 5, 1921 1,802,583 Snow Aug. 28, 1931 2,565,341Arispe Aug. 21, 1951 2,665,119 Broman Jan. 5, 1954 2,669,810 Carlson etal Feb. 23, 1954 2,716,021 Evans Aug. 23, 1955 2,762,610Puhr-Westerheide Sept. 11, 1956 2,809,018 Broman Oct. 8, 1957 FOREIGNPATENTS 726,744 Great Britain Mar. 23, 1955

